barack obama met nelson mandela when he was just a junior senator here in 2005. and years later his wife had the chance to tell mandela what he meant to her and the president. >> you cannot imagine how important your legacy is to who i am, to who my husband is. i just said, thank you, thank you, thank you. >> reporter: so back during his first visit there was little wonder why, watching a 71-year-old man dance could please so many. it was the walk that preceded it. when i met mr. mandela there was time for one question. mr. mandela, i asked, what is the one thing in life you know for sure? with that elegant smile he answered, good and evil are constantly at war. good men must choose. with defiance and dignity in equal measure. nelson mandela chose and america loved him for it. >> this was at 4:00 in the morning. >> that's right. >> thanks very much. appreciate it. we'll be right back. through all of our energy operations, we invest more in the u.s. than any other place in the world. in fact, we've invested over $55 billion here in the last five years - making bp